Radius former for end mills



May 27, 1947. L'SNEVA 2,421,358

- RADIUS FORMER FOR END MILL Filed June 16, 1944 4 Sheet-Sheet 1 4 Sheets-Sheet 2 Filed' June 16, l944 mum INVENTOR. f/YGOLf' S/VE m.

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i 27, 1947- l. SNEVA 2,421,358

- RADIUS FORMER FOR END MILL Filed June 16, 1944 4 Sheets-Sheet 3 May 27, 1947. SNEVA RADIUS FORMER FOR END MILL Filed June 16, 1944 4 Sheets-Sheet 4 INVENTOR. IXOL F (SA 5W7 NEYJI I Patented May 27, 1947 RADIUS FORIVIER FORZ'END MILES lhgolf Sneva, Bedford, Indi, 'assignor2 to WwFL Meyersaflompany; 'Be'dford," Indi at corporation s Cfaims.

:31 "Thisi'nvention "relates to an apparatus 'for grinding the spiral. fluted rend ofan endmill" or cutting tool to a prescribed. radius of curvature,

including grinding the relief back of" the spiral and cutting edge, reference being hadtc'myapplication 'Serial'No; 513396,- filedDecember -11, 1943, entitledR;adius-angle toorformeri 'It isusuaIIy required. of. an "end mill that the spiral' flutedcutting ends be'of aiprescribed' radiusvwithin very closetolerances; astmay be'requilted; bythe work being out. However, there is considerable diflicultyirr rindingtthe'spiralfiuted cuttihggedgesnof. an. end mill to an exact prescribed; radius. is largely due to" theiact that the fluted .Icutting endof. themilii spirals inwardly which makes it prl'ictica'lly impossible to-measure. .Thusthe practice hasgenerallybeen to, grind'the endoffthelmilll to produce the,prox-- imate radius. withlfnequent' checking thereof'by a a recessed or bored templet.

Also,.itis desirable torelieve that portion'of the V spiral fluted cutting end immediately behind the cutting edge to provide clearance and escape of. the metal being .cut'i'nto "the groove between -the flutesl This r'eli'e'fi'has .usually'been handground'. to a merev proximate radius: conforming to theground radius or the, end cutting end;

It. is the purpose of this invention toprovide an. attachment for the radius-angle tool former disclosed in the. above application f or; letters patent, such.as.= wil1-enable an operator to conveniently set the device totaccurately. grind "the prescribedrradius with means torotate the end mill or "tool to follow" the spiralelea'd oi the cutting edge as it is being I groundand v according to the angleofpitch.

Another feature oi the invention residesnin structure for supporting themill or tool for rotationiwhile. beingv ground :ior permitting. its contactiwith the a grinding wheel to? follow: the. spiral curvature ofthe .flutes providing the cutting edge;

still a further-feature of ttherinventionz resides in the indexing-ref the/tool supportingrmember for IOC'EtiI'Ig-it'ill; grinding. position for: eachsof. the spiral flutes according, tothe; number and spacing thereof,v and additionally rotatably indexing the tool .for -simila'r1y grinding the relievedor clearanceportionlimmediatelyfollowing ;the 1cut ting} edgettorthe same prescribed? radiusft curvature';

Theatullznaturelof the-invention will .beunderfollowingzdescriptiom andlclaims 'Fig. lis-a side elevation of the-tool former with, the end- "radius grinding attachment mounted thereon. Fig.2 is'a plan view thereofi Fig. an endelevation; 4 is a'central vertical section through the tool supportingan'd rotating collet. Fig. 5" is a' section taken on the --l"i'ne -5 -"5- of "Fig; 4' withthe-colletremoved; -Fi'g. '6""isanenlarged -cliagrammatical illustration showing one: position of thetool and grinding wheel at the beginning of the operation. Fig; 7 is thesame as 6;;'showing"- intermediate'rela-tiye positions dfithe tool andgrinding wheel; Fig; 8 isthe same asFig; 6, "showing the final' relativepositionof the tool with respect "tothe grinding wheel.

In the drawings there is illustrateda radius former for "end mills attached t'o--atoo1*fbnner as disclosed-in my .said application for Letters Patent Serial-No: 5133896; The *formeris adapted to be'securedtoan adjustablebed-plate HI on a grinding table'- in adjustable relation to the usual motordriven cupped grinding wheel 11 I l'. The formerilrcludes' a base l'2 having an annular base plate" Hw-adapte'd" to*besecurely clamped-to the; bed'plate" Ill by anysuitabl'e means Said baseplate is -provided"with a-turntable I 5, both the base platetand'turntablecarrying an annular verni'er' scale: as" indicated at I 6: Mbunt'ed-upon the turntable thereis an elongated slide 'l'l'slidable diametrically thereon. Carriedonsaid slide IT there is a transverse "slide H3 slid'able 1 transversely of the elongated slide. Thus; the slides IT and l8f 'provlde a compound slide'supp'ort} the latter carrying a vertical and upwardly extending post l9;

' Sl'idably'mounted for vertical adjustment upon thehpost f9 thereisa supporting block 20 carryihg twonp'airs or supporting rollers 2i which are freely rotatable thereon. Cradled upon said rollersz forufreerotation therewiththere is provided a cylindrical collet. housing 22 rotatably clamped onlsaidemllersby a top-bearing roller 23'; =Sai'd top-bearing roller is "freely" and 'rotatably carried near the upper endQofthe' post I 9 by a carriage h1ock.24'., Said blbckf24, with its bearing roller, i'sreadiIy removah'le'fromengagement with the coll'etlhousing'onthe'rollers H bya thumb screw 25.1

The rcolletihousingfl', which is clamped hetiweenithe rollers'2l and 23' but free'to rotate therebetween, is provided Withan inner sleeve 26 .(EigA). 11 having spaced and offset cam shoulders -ZILUZllIfor camming. ortwedgingrengagement with corresponding shoulders on theopposltelyspllt colletlzfl. Said collet' is; provided'with' the" usual longitudinal splits directed inwardly from op"- posite ends alternately in which the end mill or cutting tool 30 is bodily clamped throughout a substantial length thereof through the wedging action of the sleeve 26, upon tightening the threaded end flange 3|.

Surrounding the tool 30 and secured to the end of the collet housing 22 from which the tool extends (Fig. 4) there is an indexing collar 32 having a radially extending flange provided with a series of notches 33 in the peripheral edge thereof (Fig. Rotative movement of the collar 32 correspondingly rotates the housing 22, the collet and the tool 30. Surrounding the collar and free therefrom for relative rotation, there is provided an oscillating rin 34 which closely embraces the collar 32. Extending upwardly from the upper portion of said ring there is an extension 35 to which a plate 36 is secured by the screws 31 so as to be removable therefrom. Said plate has a head portion 38 carrying a set screw 39 adapted to be adjustably screwed through the head 38 to engage a compression spring 4!) bearing upon a plunger 4| slidably mounted to engage the notches 33 spaced about the collar 32 under spring tension. Manual turning of the housing 22 and collar 32 indexes the tool from one position to another determined by the relative positions of the notches,-upon forcible application suflicient to compress the spring 40, the application bein applied by hand to the knurled end flange 3|. Thus, as shown in Fig. 5, there are twelve such notches which permit indexing of the tool to twelve difierent positions.

As illustrated in Figs. 6, '7 and 8, the tool 30 is oscillated relative to the grinding wheel I I about a radial center indicated at A for grinding the end of the tool to the prescribed radius a. However, the grinding action must follow the spiral flutes during the processing. It is also necessary to index the tool in accordance with the number of flutes and their relative spacing. This is accomplished in the manner above described by indexing the tool through rotation of the collar 32 from engagement by the pin 4] in one notch 33 to engagement in a succeeding notch. As herein shown, the twelve notches provide for indexing a tool having up to six flutes. Wherein there may be six flutes, every other notchlocates the tool for grinding a flute and every immediate notch locates the tool for grinding the relieved or clearance portion of the flute following the cutting edge. Wherein the tool, as illustrated herein, has four flutes, the indexing thereof will bring a flute into rinding position by rotating the collar for engagement by-the plunger with every fourth notch, engagement with the next succeeding notch bringing the clearance portion of the flute into position for grinding.

In order that the grinding operation will follow the contour of the spiral flutes as the tool is oscillated about its center of oscillation A, the followin camming mechanism is provided. The lower portion of the oscillating ring 34 is provided with an extension indicated at 34a having a pin 42 to which a laterally extending cam follower rod 43 is adjustably connected. Extending upwardly into the path of said rod there is an adjustable cam block 44. The rod 43 is held in engagement with the cam block under spring tension by the spring 45 having one end connected to the extension 34a and theother end connected to a is oscillated back and forth in the following described manner, it imparts an oscillatory movement through the rod 43, ring 34, plunger 4|, and

collet 29 to the end mill or tool 30. Thus, the tool 30 is caused to rotate about its axial center ac- COI'ding to the setting of the cam block.

For supporting the cam block there is a detachable bracket 46 having lower bifurcated jaw members 41 adapted to be mounted over and secured to the stationary base table [2a. Said bracket is provided with an inwardly extending arm 48 which lies over the axial center of the turntable I5. Pivoted upon said arm there is secured in rotative adjustment a head 49 having a tangentially extending slotted arm 50. The cam block 44 is mounted on the arm 59 to be locked by a set screw 5| adjustable longitudinally of the slot in the arm 59, and about which the cam block may be rotatably adjusted. For convenience of adjustment, the cam block is provided with an upwardly extending portion 52.

The bracket 46 is secured to the base plate In with the rotative mounting of the head 49 lying in the axial center of the turntable. Thus, the slotted arm 50 carried by the head may be swung to varying positions about the axial center of the turntable and the cam block may be adjusted thereon to varying rotative positions about the set screw 5| and shifted longitudinally of the arm 50. By setting of the arm 50 and cam block 44 relative to the cam follower arm 43, oscillatory movement of the turntable will cause the tool to rotate about its axial center as it is swung about the radial center A during the grinding operation. Thus, contact of the spiral flute with the grinding wheel is continuously controlled and maintained by the setting of the arm 50 and cam block 44 to follow the spiral lead of the flute.

For centering and setting the tool, the elongated slide I! is adjusted longitudinally and diametrically of the turntable by a hand wheel 53 mounted on a screw shaft extending through the screw blocks 55. A Vernier scale 56 is provided for indicating the extent of revolution of the shaft and relative position of the slide and turntable. The transverse slide I8 is slidably mounted upon suitable guideways carried by the elongated slide H and is adjustably positioned by the rack and pinion 5'! actuated by the hand lever 58. The elongated slide I? carries a pair of spaced setting blocks 59 and 59a, provided with set screws therein and adapted to receive a prescribed gauge block. The transverse slide 18 carries a laterally extending pin 60 positioned to abut against one of said set screws for initially centering the tool. A gauge block may thenbe interposed for centering the tool to a prescribed radial center A as may be determined. Through manipulation of said slides, the determined center A of the radius to be ground is brought into alignment with the axial center of the turntable.

The turntable carries a radially extending stop arm 6| engageable with the stop block 62 adjustably positioned by the set screw 63 about the periphery of the base plate 12a. The elongated slide I1 is provided with a locking lever 64 for looking it in adjusted position, the turntable carrying a similar locking lever 04a for locking it against rotation relative to the base. Also, the transverse slide It may be locked in adjusted position by the locking screws 65.

For forming a predetermined radius on the end mill, it is rigidly clamped within the collet, and the bracket 46 carrying the cam block is mounted upon the base table and adjusted thereon so that the center of the head 49 is in the axial center of the turntable. The slide I8 is moved to the left: (Figs 3). to* engage. apreviousl'y adjusted set screw the block 59 to'- position the axial center of: the tool andi coll'et in; intersecting relation with: the axial center of the turntable; Thereupon the setting for any desired? radius may be made by movin'gi'the slide 81 to "the" right, measuring with. a. micrometer half! the diameter of the tool less" the: prescribed radius. and interposinga gaugeblbck so determinedi betweent.the screwofblbckEQ and the pin 66 ont'heslide. .In this mannenthe cent'er' A of the radius? tov be ground. lies in the i axial center or the. turntable.

The grinding. table Iflis adiiuste'd until the grinding wheel H touches the .si'de oftthe Lend mill, as in Fig. :6, whereupon thesgrindin'g. table is moved longitudinally sothatitheen'd mill-Iris retractedito clear thewheel. ..'Ilie'turntable is then rotated 90' degrees and .the grinding table again moved longitudinally toward the wheel until the nose ofthe tool is positioned to: engage the wheel. by :movement of slide 11. .At this position the reading. on the vernier scale-5t is noted. The slide l 'l is then retracted. so that the corner of the tool clears theiwh'eel' when the turntable is oscillated about its '90 degree. are; With. this setting the :turntable .is oscillated: "back and fort'h' with: the tool: ingrinding engagement with the wheel whichiis' thenxbeing' rotatedffor grinidingaction thereon. As 'the grindih'g' action eats into the end corner'oflthe tool (Fig; 7) it. is fed into? the grinding who e13 by: advancing. the slide I lilfit'hrough manipulation: of the hand. wheel 53". Each oscillation .through. the '90 .degreeiarc limited. by theistopsvfi I and..62', causestthe' tool: to be. rotated aboutrits 'aXial."center'tthrough the action of the spring. 45 and cam block. 44 engaging the rod 43 to move the .rod: upwardly and thereby rotate the colleti' holder on the rollers 2|. This action of thecanr block when: properly adjusted causes the grinding contact :between the: tool and the wheel to" automatically-follow the spiral curvature of the flutet'being ground.

It" may be noted that the base? lfl is supported and clamped to1t-he= grind'ing table I El at ta slight angle which isacontrolle'dl by the diameter of the bar l ll'a lying in. the V-gr.oove lilb lprovidedfiin thebottom ofithe base. Thisihas thereifect: of providingthe desired clearanceuangle between the tool and I grinding? wheelfasxshown. inJEig. ..1, and to develop 'theicuttin'g edge: of the flute;

As the; grindingprogresseatthe "slides I1 is ad'- vanced untilthe. originali'rea'ding on the Vernier. scaleJSfiis reached; it being noted that the slide after being set at the original reading was backed off so that the corner of the tool cleared the wheel. Atthis point the operation upon one of the flutes has been completed. As indicated. inFig. 8, the tool is ground as to one of its spiral flutes from a square nose'as'in Fig. 6, totheprescribed radius a aboutthe center of curvature A.

Having completed the grinding of one-flute, it is then desirable to grind thefollowing relief or secondary clearance angle to the sameradius. For this purpose the indexing collar Slide-manually rotated by the threaded end flange 31' to bring the plunger into locking engagement with the following notch 33. The grinding operation above described is thenvrepe'ated to grind the flute slightly. behind theicuttingedge previously ground to provide clearance. Following the grinding of the cutting edge and clearance of one flute, the indexing collar is then adjusted to a succeeding notch 33 to bring the next flute into position for the grinding operation. This is repeated until each of the flutes followed by their respective: clearances. have been :ground'. to precisely the-prescribed radius, such grinding followingthespirali inwardly directed curvature thereof As above mentioned, the prescribed radius a to which the tool is to be ground, is obtained by measuring the radius of the end mill, deducting therefrom the desired. radius, providing a auge bloclncorresponding. to. this difference and placing it between: the pin bfl 'an'd the set screw of theblock 39'. Since the center of the collet and tool lies=intheaxialzcenter ofthe turntable when pin-Gil engages the set. screw of block 59, such gaugeblockrwill thereby set the center A in line with'th'e axial center of the turntable so that oscillation thereof will swing the tool back and forth about saidcenter A. Amicrometermay be used for such: setting inplace of a gauge block, if 1 desired.

For setting of the cam block to cause the tool to be turned in accordance with the: spiral curvature of the flute, a surface gauge is employed; By slowly oscillating the turntable and holding'the pointer of the surface gauge against one ofthe flutes to be ground, the cam 44 may beadjusted so that at each position of the turntable the surface-gauge will be in line with the flute; when the adjustment is completed so that the flute will follow'the pointer of the surface gauge during the 9O degree movement of the turntable; thecam is secured in such-position. Having thus been set,.the action becomes automatic in respect toall flutes andtheir relieved clearance throughout the repeated oscillation required to grind them to the prescribed radius. From the foregoing, it will be noted that the adjustable cam l l actsto automatically turn the tool to compensate for the lead in of the spiral flutes, thereby providing cam controlled rotary movement of the end: mill to. follow the particular'lead of its spiral'ifiutesin-accordance with the setting of the cam.

The invention claimed is:

1. Apparatus for forming a prescribed end radius-on a spirally fluted outting'tool, including a-base member, an oscillatingturntable pivotally mounte'd thereon a compou'nd slide carried by .sai'd tur-ntable; arot-ary support. for securing said tool mounted on said slide, whereby said tool is simultaneously oscillated through movement of saidturnt'able and fed through movement of said slidei'nt'o flut'e grinding contact'with a rotating grinding wh'eel; a camiadjust'ably mounted on said base member, and: a cam follower secured to said rotary'support engageable with and movable by said cam upon oscillatory movement thereof for causing controlled rotative movement ofsai'd tool about-its axial center'according tothe spiral curvature of-saidflute.

'21 Apparatus for forming a prescribed end radius on a. spirally fluted cutting tool, including a base member, an oscillating turntablepivotally mounted thereon, a compound slide carried by sai'cl turntablaa rotarysupportfor securing said tool mounted onsaidslide, wherebysaid' tool is simultaneously oscillated through movement of said slide ihto' flute'grinding contactwith a-rotating' grinding wheel, a. bracket removably secured to saidibase member and extending oversaid turntable, an adjustable cam carried by said bracket, a spring controlled cam follower engagea'ble with said cam, and means for connecting said cam follower to said rotary support, whereby oscillatory movement of said support and tool by said turntable will effect a controlled rotative movement of said tool about its axial center, the relation of said cam to said follower being such as to cause said rotative movement to follow the spiral curvature of said flute and maintain contact thereof with said wheel during the oscillatory grinding action.

3. Apparatus for forming a prescribed end radius on a spirally fluted cutting tool, including an oscillating turntable having a, rotary support upon which said tool is secured, whereby said tool may be oscillated with its flute in grinding contact with a rotating grinding Wheel, a fixedly supported cam, and a cam follower carried by said rotary support, a spring operatively connected with said cam follower to maintain it in contact with said cam under spring tension, said cam being adjustable relative to said rotary support and turntable for causing controlled rotative movement of said tool to compensate for the spiral curvature of its flute during its oscillatory movement relative to said grinding wheel.

4. Apparatus for forming a prescribed end radius on a spirally fluted cutting tool, including a 'base member, an oscillating turntable pivotally mounted thereon, a compound slide carried by said turntable, an upstanding post mounted on said slide, a series of rollers adjustably mounted on said post, a support for securing said tool rotatably mounted between said rollers, means for adjusting said slide upon said turntable for centering said tool relative thereto for grinding engagement with a rotating grinding wheel, whereby oscillation of said turntable will cause the grinding of the end of said tool to a prescribed radius, a cam follower secured to said tool support, and a, cam secured to said base member adjustable for engagement by said cam follower for causing controlled rotative movement of said tool about its axial center as said turntable is oscillated, said cam being so adjusted as to thereby maintain said flute in effective grinding engagement with said wheel during said oscillatory movement for grinding it to the prescribed radius.

5. Apparatus for grinding a cutting tool having a, plurality of equally spaced spirally formed flutes, including a support movable relative to a rotating grinding wheel, a collet for supporting said tool, a cylindrical holder for said collet adapted to compress it into tool clamping position, a series of rollers for rotatably supporting said cylindrical holder. said rollers being mounted upon said movable support, a peripherally notched flange secured about said holder, a ring surrounding said flange, and a spring pressed plunger slidable in said ring for engagement and disengagement with said notches for locating said holder in different predetermined spaced rotative positions, said notches being spaced about said flange in predetermined relation to the flutes on said tool for locating the respective flutes for grinding.

6. Apparatus for forming a prescribed end radius on a spirally fluted cutting tool, including a base member, an oscillatory turntable pivotally mounted thereon, a compound slide carried by said turntable, a rotary support for securing said tool mounted on said slide, whereby said tool is simultaneously oscillated through movement of said turntable and fed through movement of said slide into flute grinding contact with a rotating grinding wheel, a cam adjustably mounted on said base member, a cam follower secured to said rotary support engageable with and movable by said cam upon oscillatory movement thereof for causing controlled rotative movement of said tool about its axial center according to the spiral curvature of said flute, and an indexing mechanism interposed between said rotary support and tool operable to positively locate said tool in successive positions to present thereto for individually grinding each of its respective flutes,

7. Apparatus for forming a prescribed end radius on a cutting tool having a plurality of spaced spirally extending flutes, including an oscillating turntable having a rotary support on which said tool is secured, whereby said tool may be oscillated with its flutes in grinding contact with a rotating grinding wheel, a cam carried by said apparatus and adjustable thereon, cam follower mechanism carried by said rotary support operable by said cam to cause relative movement of said tool about its axial center according to the spiral curvature of said flutes upon oscillation of said turntable, and an indexing mechanism interposed between said rotary support and tool operable to locate said tool in successive positions relative to said support and grinding wheel for presenting thereto and individually grinding each of its respective flutes.

3. Apparatus for forming a prescribed end radius on a, cutting tool having a plurality of spaced spirally directed flutes, including an oscillating turntable having a rotary support upon which said tool is secured, whereby said tool may be oscillated with its flutes in grinding contact with a rotating grinding wheel, a cam carried by said apparatus, a cam follower connected with said rotary support engageable with and movable by said cam upon oscillatory movement thereof for causing controlled rotative movement of said tool about its axial center according to the spiral curvature of said flutes, a series of spaced peripherally positioned notches extending about said rotary support, a driving ring mounted about said notches connected with said cam follower, and a spring pressed plunger mounted in said ring engageable with said notches under spring tension for indexing said tool to different positions relative thereto to positively locate it in successive positions to present each of the respective flutes to said grinding wheel.

INGOLF SNEVA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 571,336 Budlong Nov. 17, 1896 1,095,338 Mallory May 5, 1914 2,212,855 Chittenden Aug. 17, 1940 2,332,510 Franzen Oct. 26, 1943 1,791,776 Wahl Feb. 10, 1931 FOREIGN PATENTS Number Country Date 111,433 Great Britain Nov, 29, 1917 

